exxos blog - random goings on

[exxos]

Looks like M851 might be what I am looking for as it reports 0.14 currently. Will check more when my print ends.

EDIT:
Does not seem to change in value, so must be "baby step" offset.

EDIT2:

G30 might be it

https://marlinfw.org/docs/gcode/G030.html

[exxos]

Seems the probing has issues as well

Code: Select all

SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 219.90 Y: 220.00 Z: -0.23
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 219.90 Y: 220.00 Z: -0.50
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 219.90 Y: 220.00 Z: -0.23

I guess this explains why ABL seems to make things incredibly worse.. I guess I will go do some hard calibration elsewhere...

Code: Select all

SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 59.90 Y: 31.00 Z: 0.21
echo:busy: processing
>>> G30
SENDING:G30
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 59.90 Y: 219.78 Z: 0.21
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 59.90 Y: 219.78 Z: 0.22
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 59.90 Y: 219.78 Z: 0.24
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 59.90 Y: 219.78 Z: 0.20
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 59.90 Y: 219.78 Z: 0.21
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 59.90 Y: 219.78 Z: 0.21
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 59.90 Y: 219.78 Z: 0.22
>>> G30
SENDING:G30
echo:busy: processing
echo:busy: processing
echo:busy: processing
Bed X: 59.90 Y: 219.78 Z: 0.23
>>> G30
SENDING:G30
echo:busy: processing

[Badwolf]

@exxos I use a bltouch which most firmware supports as standard, then do an auto bed level before each print by putting the gcode G29 in the startup code in Cura.

Yeah, I have one of those. It's not great, but kind of sort of works.

No experience with the magnetic ones, so wouldn't know how to get a reading. My guess would be it's got an on board comparator and just outputs a yes or a no, though.

M851 is what sets (and queries) the Z-probe offset and M500 is what saves the configuration to flash for me.

BW

[exxos]

I tightened up the bed as much is possible and got a reasonably consistent 1.80mm gap now. However this leads me to yet another problem

As I was on doing the Z-end stop bodge board, I noticed the lights were flickering on and off which puzzled me..

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It seem to always happen as I tightened up the nut... I wondered if it was board flex or something shorting out but I could not see anything obvious going on..

So I tested the voltage on the front and the back of the board, and one of the flood fills is connected to 3.3V!!!!!!!

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I mean seriously, what fu**ing idiot designs a board with a screw hole for clamping the board, which is generally to a frame which is connected to gnd, and fu**ing flood fills what it is tightening up against with 3.3V ?! I mean seriously

[exxos]

It do! for now....

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[PhilC]

Thats looking much better now.

When I do an ABL I fIrst manually level the bed on each switch on of the printer, then do the ABL.

[exxos]

Thats looking much better now.

When I do an ABL I fIrst manually level the bed on each switch on of the printer, then do the ABL.

Something is still wonky with ABL. The probe can read about 0.05mm off at random.

There is still something up with z homing. But its hard to track down. I've noticed there is some play in the z nuts which move on the threaded bar.so it could be that for starters. But I also think the bed extrusions and those stupid wheels are shifting as the bed moves about. I really need linear rails on that as well

[exxos]

While updating the H4/H5 troubleshooting thread I un-forgot I designed this..

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.. back in Nov 16, 2020 It's actually a diagnostic card which will output the first several databus bits onto LED's for quick diagnostics to what is happening. I need to finish that at some point

[exxos]

Been plotting how to fit the linear rails..

These things are larger than I thought they were While I could bolt them down, I'm slightly concerned about the distance from the drive belts to the actual bed I would have to build a block to keep it stable but not sure that is something I really want to do.

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I then started plotting fitting the rails to the outside of the existing ones..

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Then I noticed what the problem is with the Y-axis

The exclusion is actually bent along its length. It is bolted to the chassis at the rear of the printer base but not actually fixed to anything at the front. So it is actually bending upwards.

In the centre there is a horizontal exclusion where they have machined out the Y-axis extrusions, but I think they have not machined enough out of them. It is actually bent upwards in the middle and the whole thing is just bent out of shape from front to back

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So I am starting to think I should go whole hog and replace the whole assembly now

Should be easy enough to drill the plate with holes. Problem is the rear of the unit also has the motor on a bracket to the extrusions. So likely that is going to be a huge problem. Along with the tensioner at the front. I will likely need a different belt system The linear rails are 15mm and the existing extrusions are 20mm. so ideally I need to find a 20mm rail system.

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[exxos]

Only place in the UK I could get the larger 20mm rails from was evilbay The price on those things varies that much it is unbelievable. I just went for a cheap kit of 20mm x 400mm with 4 runners for £50. In RS you can easily pay over £100 just for one single rail!

At least the end plates will fit directly onto the new bar. I will probably have to drill new holes in the plates is not much of a big deal I guess. I think the main problem is going to be securing the bar to the frame as the holes will not line up with the existing ones

While I have the circuit board exposed I will reseat the connections and put contact grease on them all. It will reduce the likelihood of the Z-sensor continuing to go nuts at random.

On my travels I also noticed these type of things..

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Thought they were pretty call using a threaded bar instead of a belt... Must.. Resist....


EDIT:

The bodge cut out which wasn't good...

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It would have been better if they had just left it flat like it was originally rather than hacking a piece out of it.

In fact I don't really like this " balancing stuff in the centre" type of stuff that everything seems to be based around. It would have been better to have another bar across the back at least to have the whole thing level supported from the middle and the rear not just the centre. I'm actually half tempted to do that but more work again